EP 0 847 807 A2 discloses an electrostatic paint application device. In this case, a low-voltage source, accommodated in an explosion-proof housing, having an electric generator is arranged remotely from a spray gun. The low-voltage source is connected to the housing of the spray gun by a low-voltage cable. The low-voltage source is suited to being accommodated in a spray booth and in a hangar in which an aircraft is painted with the enamel paint. The spray gun has three external connections. In addition to the low-voltage cable, the spray gun is connected to a compressed air hose and to a paint hose. The compressed air hose is connected to a conventional compressed air source, namely a compressor. The paint hose is connected to a pressurised paint tank which contains the enamel paint. When a person operating the spray gun presses a switch on the spray gun, an air valve of the spray head is opened to release a flow of sprayed air. In connection therewith, a paint valve which is also arranged on the spray head is opened to release a flow of paint.
The low-voltage cable applies a low direct voltage to the spray gun. The voltage can be at a controlled level of between 0 and 10 volts of direct current. This voltage is applied to the input of a conventional high-voltage source which is inside the spray gun. The high-voltage feed contains an oscillator which converts the input direct voltage into an alternating voltage at a higher level. The alternating voltage is then applied to a capacitor and diode network which multiplies the voltage and converts it into a direct voltage at a very high level, as is generally known in the prior art. The actual level of the voltage depends on the level of the input direct voltage. Adjusting the level of the applied direct voltage at the low-voltage cable adjusts the level of the high voltage which causes the electrostatic painting.
DE 10 2008 000 397 A1 describes a conventional spray gun which, in its basic structure, is similar to the spray gun described above, but which works without electrical means for electrostatically charging the jet of paint. A conventional spray gun of this type is also capable of being used within the scope of the device according to the subject-matter of the invention.
A disadvantage of known spray guns is that they are operated manually along the surface by a handle piece which is arranged near the operating switch of the spray gun, so that surfaces of aircraft parts which are particularly low-lying and are directed obliquely downwards can only be reached with a considerable amount of physical effort. Such working conditions are tiring and in the long run are harmful to health. In the general prior art, solutions are already known in which the spray head of a spray gun is configured as a type of lance, so that the spray head is arranged at a relatively great distance from the other components of the spray gun. However, this solution cannot produce paintwork of a satisfactory quality, since on the one hand, an electrostatic charge of the enamel paint is not ensured and on the other, the guidance of the spray head cannot be manually controlled in an adequately precise manner.
An aspect of the present invention provides a device for manually painting a large surface using a spray gun, which device allows an ergonomically improved handling of the spray gun, in particular for painting low-lying and downwardly directed surfaces of aircraft parts, the device not impairing the quality of the paintwork.